[jdk21u-dev] RFR: 8320379: C2: Sort spilling/unspilling sequence for better ld/st merging into ldp/stp on AArch64

[Xiaolong Peng]

Backport JDK-8320379: C2: Sort spilling/unspilling sequence for better ld/st merging into ldp/stp on AArch64

### Validation

Tested on AWS Graviton instance by running ```JTREG_KEYWORDS="!headful & !external-dep & !printer" make test TEST=all```, same the test for PR on jdk17, only saw few test failures in CAInterop.java and compiler/intrinsics. 

- CAInterop tests are known intermittently failing tests, it should be fine to ignore. 
- The test failures from compiler/intrinsics has error message "Option 'UseSHA3Intrinsics' is expected to have 'true' value Option 'UseSHA3Intrinsics' should be enabled by default", it seems a bug but not related to the backport, will follow up we need to create a bug.

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Commit messages:
 - Backport 3ccd02f14211a3384f27fba1633f9d8421378c9a

Changes: https://git.openjdk.org/jdk21u-dev/pull/665/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=665&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320379
  Stats: 40 lines in 1 file changed: 37 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/665.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/665/head:pull/665

PR: https://git.openjdk.org/jdk21u-dev/pull/665